Wireless communication device and radio communication system using the same

ABSTRACT

A wireless communication apparatus has a current system and a standby system independent of each other. An interface circuit la of a radio  10   a  outputs two signals input from an MUX device  101  as a signal of a current system and a signal of a standby system to a V polarization transmitter/receiver  2   a  and an H polarization transmitter/receiver  3   a . Signals transmitted from the V polarization transmitter/receiver  2   a  and the H polarization transmitter/receiver  3   a  are received by a V polarization transmitter/receiver  2   b  and a H polarization transmitter/receiver  3   b  of a radio  10   b , and output to the interface circuit  1   b . Then the interface circuit  1   b  transmits a signal of the current system and a signal of the standby system from the V polarization transmitter/receiver  2   b  and the H polarization transmitter/receiver  3   b  to the MUX device  102.

TECHNICAL FIELD

The present invention relates to a wireless communication apparatus anda wireless communication system for use with the apparatus, and morespecifically to a wireless communication apparatus having a redundantconfiguration and a wireless communication system for use with theapparatus.

BACKGROUND ART

Conventionally, a radio for microwave digital communication in STM-N(synchronous transport module-level N) transmission uses an MSP(multiplex section protection) system as a system for support of duplexof STM-N interface. The MSP system is described in, for example, theITU-T Recommendation G.782 or G.783, etc.

The wireless communication system for performing wireless communicationbetween the above-mentioned radios is explained below by referring tothe (1+1) configuration which is the smallest configuration of the (N+1)configuration as the configuration of each radio. FIG. 1 shows theconfiguration of the conventional wireless communication system.

As shown in FIG. 1, the conventional wireless communication system isconfigured by radios 30 a and 30 b and MUX devices 101 and 102. Theradio 30 a is configured by an interface circuit 21 a, a currenttransmitter/receiver 22 a, a standby transmitter/receiver 23 a, acirculator 24 a, and an antenna 25 a. The radio 30 b is configured by aninterface circuit 21 b, a current transmitter/receiver 22 b, a standbytransmitter/receiver 23 b, a circulator 24 b, and an antenna 25 b.

The MUX devices 101 and 102 are connected to the respective node devicesnot shown in the attached drawings, and each of the MUX devices 101 and102 multiplexes an input signal from a node device connected to it,branches the multiplexed signal (STM-N signal), and then transmits thetwo same branched STM-N signals to optical transmission lines 210 and220 (250 and 260).

The two STM-N signals output from the MUX device 101 is input to theinterface circuit 21 a of the radio 30 a through the opticaltransmission lines 210 and 220. The interface circuit 21 a selects oneof the two input STM-N signals, branches the selected signal into twosignals for transmission through the current radio circuit and thestandby radio circuit between the radios 30 a and 30 b, and then outputsthe branched signals to the current transmitter/receiver 22 a and thestandby transmitter/receiver 23 a.

Each of the current transmitter/receiver 22 a and the standbytransmitter/receiver 23 a modulates an input signal, converts themodulated signal to a radio frequency of an RF band, and then transmitsthe conversion result to the radio 30 b which is an opposite stationthrough the circulator 24 a and the antenna 25 a. The signal (the signalfrom the current transmitter/receiver 22 a and the signal from thestandby transmitter/receiver 23 a) received through the antenna 25 b ofthe radio 30 b is input to the current transmitter/receiver 22 b and thestandby transmitter/receiver 23 b through the circulator 24 b.

Each of the current transmitter/receiver 22 b and the standbytransmitter/receiver 23 b converts an RF received signal to a signal ofan intermediate frequency band, demodulates it, and outputs a base banddigital signal which is a demodulation signal to the interface circuit21 b. The interface circuit 21 b selects one of the two input base banddigital signals from the current transmitter/receiver 22 b and thestandby transmitter/receiver 23 b, branches the selected signals intotwo signals, and then outputs the branched signals to the MUX device 102through the optical transmission lines 270 and 280.

The frequency distribution at the radio frequencies of the current radiocircuit and the standby radio circuit between the radios 30 a and 30 bis the interleave distribution as shown in FIG. 2B. That is, the currenttransmitter/receivers 22 a and 22 b use the frequency F0 shown in FIG.2B, and the standby transmitter/receivers 23 a and 23 b use thefrequency F2 shown in FIG. 2B.

FIG. 3 shows the configuration of the interface circuits 21 a and 21 bshown in FIG. 1, and the components also shown in FIG. 1 are assignedthe same reference numerals. As shown in FIG. 3, each of the interfacecircuits 21 a and 21 b is configured by STM-N input interface circuits31 and 32, a selection circuit 33, a control circuit 34, a branchcircuit 35, a selection circuit 37, a branch circuit 38, STM-N outputinterface circuits 39 and 40, and a CLK providing circuit 36. The CLKproviding circuit 36 provides a generated clock to the STM-N inputinterface circuits 31 and 32 and the STM-N output interface circuits 39and 40.

The two STM-N signals transmitted from the MUX device 101 to the opticaltransmission lines 210 and 220 are input to the STM-N input interfacecircuits 31 and 32 of the interface circuit 21 a. Each of the STM-Ninput interface circuits 31 and 32 performs signal processing of MSOH(multiplex section overhead), which is an overhead signal of an inputSTM-N signal, and signal processing of transferring the input STM-Nsignal from the CLK providing circuit 36 to a clock to be provided. Eachof the STM-N input interface circuits 31 and 32 monitors the quality ofthe input STM-N signal, and outputs the monitor result to the controlcircuit 34.

The control circuit 34 controls the selection circuit 33 to select asignal having better signal quality from between the two STM-N signalsbased on the monitor result from the STM-N input interface circuits 31and 32. The selection circuit 33 selects a better signal from betweenthe two signals from the STM-N input interface circuits 31 and 32, andoutputs the selected signal. The branch circuit 35 branches the signalfrom the selection circuit 33 into two signals, and outputs them to thecurrent transmitter/receiver 22 a and the standby transmitter/receiver23 a.

Meanwhile, the two signals output from the current transmitter/receiver22 a and the standby transmitter/receiver 23 a are input to theselection circuit 37 of the interface circuit 21 a. The selectioncircuit 37 selects a signal from the current transmitter/receiver 22 afrom between the two input signals, and outputs the selected signal. Thebranch circuit 38 branches the signal from the selection circuit 37 intotwo signals, and outputs the branched signals from the selection circuit37 to the STM-N output interface circuits 39 and 40. When a failureoccurs in the current system, the selection circuit 37 selects a signalfrom the standby transmitter/receiver 23 a and outputs it.

The STM-N output interface circuits 39 and 40 of the interface circuit21 a convert the input signal from the branch circuit 38 to an STM-Nsignal, and transmit it to the MUX device 101 through the opticaltransmission lines 230 and 240. The operation of the interface circuit21 b is similar to the operation of the interface circuit 21 a.

[Patent Document 1]

Japanese Patent Laid-Open No. 2001-86051 (page 3, FIG. 1)

Problems to be Solved by the Invention

As explained above, each of the STM-N interface portion and a radioportion of a radio has conventionally been defined as a redundantconfiguration corresponding to the STM-N redundant configuration(duplexed optical transmission line). The interface portion selects asignal having better quality from between the two input signals from theduplexed optical transmission lines, and uses the selected signal in thecurrent and standby wireless circuits, which is the MSP system. Theradio portion has the redundant configuration of transmitting theselected signal through the current and standby wireless circuits. It iscommon to set interleave frequency distribution as frequencydistribution to be used for current and standby wireless circuits.

However, as shown in FIG. 3, there is no redundant configuration betweenthe selection circuit 33 and the branch circuit 35 and between theselection circuit 37 and the branch circuit 38. Thus, there occurs theproblem that a failure arising in the common portion having no redundantconfiguration cannot be relieved.

Furthermore, since the interface portion uses the MSP system, it isnecessary to set an MST (multiplex section termination) configurationrequested for the MSP system. That is, the CLK providing circuit 36 andan MSOH terminating circuit (which is provided in the interface circuits31 and 32 or between the selection circuit 33 and the branch circuit 35)are required.

In addition, with an interleaving frequency arrangement, an RF frequencyfor two channels is required.

The patent document 1 describes a wireless communication system in whichthe current circuit and the standby circuit are configured by a crosspolarization transmission circuit for transmission of electric waveshaving the same frequencies and different polarization directions.However, in this wireless communication system, a radio device branchesan input signal into a signal for the current system and a signal forthe standby system, and when a fault occurs in the current system, asignal of the standby system received from another radio device isselected and output using a signal switch unit of the original radiodevice. That is, in the radio device, the current system and the standbysystem is not completely separated, thereby causing the problem that acurrent system signal and a standby system signal received by the radiodevice have to be controlled and switched.

The present invention aims at providing a wireless communicationapparatus in which the current system and the standby system areindependent of each other, and a wireless communication system for usewith the apparatus.

DISCLOSURE OF THE INVENTION

The wireless communication apparatus according to the present inventionhas a redundant configuration in which an upper apparatus inputs thesame signals through a current cable circuit and a standby cablecircuit, and includes: current communication means for transmitting asignal input through the current cable circuit as a radio signal toanother wireless communication apparatus through a current radiocircuit; and standby communication means for transmitting a signal inputthrough the standby cable circuit as a radio signal to the otherwireless communication apparatus through a standby radio circuit.

In the wireless communication apparatus, the radio signals transmittedfrom the current communication means and the standby communication meansare polarization signals having the same frequencies and differentpolarization directions.

In the wireless communication apparatus, the current communication meansreceives a signal transmitted from a current communication means of theother wireless communication apparatus through the current radiocircuit, and transmits the received signal to the upper apparatusthrough the current cable circuit, and the standby communication meansreceives a signal transmitted from a standby communication means of theother wireless communication apparatus through the standby radiocircuit, and transmits the received signal to the upper apparatusthrough the standby cable circuit.

In the wireless communication apparatus, when a fault occurs in thecurrent system, the signal transmitted from the standby communicationmeans to the upper apparatus is selected by the upper apparatus as areceived signal from the wireless communication apparatus, therebyswitching the current system to the standby system.

The wireless communication system according to the present inventionperforms wireless communication between wireless communicationapparatuses which have the respective redundant configurations andreceive the same signals from upper apparatuses for the respectiveapparatuses through a current cable circuit and a standby cable circuit,and each of the wireless communication apparatuses includes: currentcommunication means for transmitting a signal input through the currentcable circuit as a radio signal to another wireless communicationapparatus through a current radio circuit; and standby communicationmeans for transmitting a signal input through the standby cable circuitas a radio signal to the other wireless communication apparatus througha standby radio circuit.

In the wireless communication apparatus, the radio signals transmittedfrom the current communication means and the standby communication meansare polarization signals having the same frequencies and differentpolarization directions.

In the wireless communication apparatus, the current communication meansreceives a signal transmitted from a current communication means of theother wireless communication apparatus through the current radiocircuit, and transmits the received signal to the upper apparatusthrough the current cable circuit, and the standby communication meansreceives a signal transmitted from a standby communication means of theother wireless communication apparatus through the standby radiocircuit, and transmits the received signal to the upper apparatusthrough the standby cable circuit.

In the wireless communication system, when a fault occurs in a currentsystem, the upper-apparatus selects a signal from the standbycommunication means of the wireless communication apparatus connected tothe apparatus as a received signal from the wireless communicationapparatus, thereby switching from the current system to the standbysystem.

Described below is the operation according to the present invention.Current communication means of a wireless communication apparatustransmits one of the same signals from the upper apparatus of thewireless communication apparatus as a radio signal to another wirelesscommunication apparatus through a current radio circuit. Standbycommunication means transmits another same signal as a radio signal toanother wireless communication apparatus through a standby radiocircuit. Thus, the wireless communication apparatus does not select oneof the same signals from the upper apparatus to branch the selectedsignals into a current system signal and a standby system signal, buttransmits the same signals from the upper apparatus to another wirelesscommunication apparatus as a current signal and a standby signal.

The current communication means receives the signal transmitted from thecurrent communication means of another wireless communication apparatusthrough the current radio circuit, and transmits the received signal toan upper apparatus. The standby communication means receives a signaltransmitted from the standby communication means of the other wirelesscommunication apparatus through the standby radio circuit, and transmitsthe received signal to the upper apparatus. Thus, the wirelesscommunication apparatus does not select one of the character string andthe standby signal and switch between the current system and the standbysystem, but transmits a current signal and a standby signal from theother wireless communication apparatus to the upper apparatus.

Then, the upper apparatus switches between the current system and thestandby system.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shows the configuration of the conventional wirelesscommunication system;

FIG. 2A shows the radio frequency distribution in the wirelesscommunication system shown in FIG. 1;

FIG. 2B shows the radio frequency distribution in the conventionalwireless communication system;

FIG. 3 shows the configuration of the interface circuits 21 a and 21 bshown in FIG. 1;

FIG. 4 shows the configuration of the wireless communication systemaccording to an embodiment of the present invention; and

FIG. 5 shows the configuration of the interface circuits la and 1 bshown in FIG. 4.

Reference numerals 1 a and 1 b designate interface circuits. Referencenumerals 2 a and 2 b designate V polarization transmitters/receivers.Reference numerals 3 a and 3 b designate H polarizationtransmitters/receivers. Reference numerals 4 a, 4 b, 5 a, and 5 bdesignate circulators. Reference numerals 6 a and 6 b designateantennas. Reference numerals 10 a and 10 b designate radios. Referencenumerals 11 and 12 designate STM-N input interface circuits. Referencenumerals 13 and 14 designate STM-N output interface circuits. Referencenumerals 101 and 102 designate MUX devices. Reference numerals 110 to180 designate optical transmission lines.

BEST MODE FOR CARRYING OUT THE INVENTION

The embodiments of the present invention are described below byreferring to the attached drawings. FIG. 4 shows the configuration ofthe wireless communication system according to an embodiment of thepresent invention. As shown in FIG. 4, the wireless communication systemaccording to an embodiment of the present invention is configured by theradios 10 a and 10 b and the MUX devices 101 and 102.

The radio 10 a is configured by the interface circuit 1 a, the Vpolarization transmitter/receiver 2 a, the H polarizationtransmitter/receiver 3 a, the circulators 4 a and 5 a, and the antenna 6a. The radio 10 b is configured by the interface circuit 1 b, the Vpolarization transmitter/receiver 2 b, the H polarizationtransmitter/receiver 3 b, the circulators 4 b and 5 b, and the antenna 6b.

Each of the MUX devices 101 and 102 is connected to a node device notshown in the attached drawings. The MUX device 101 multiplexes an inputsignal from the node device connected to itself, branches themultiplexed signal (STM-N signal) into two signals, and then transmitsthe two same STM-N signals to the down optical transmission lines 110and 120. The MUX device 102 multiplexes an input signal from the nodedevice connected to itself, branches the multiplexed signal (STM-Nsignal) into two signals, and then transmits the two identical STM-Nsignals to the down optical transmission lines 150 and 160.

The MUX device 101 selects one of the two STM-N signals input throughthe up optical transmission lines 130 and 140 as a received signal fromthe radio 10 a, divides the selected signal into a plurality of signals,and transmits the signals to the node device connected to the MUX device101. The MUX device 102 selects one of the two STM-N signals inputthrough the up optical transmission lines 170 and 180 as a receivedsignal from the radio 10 b, divides the selected signal into a pluralityof signals, and transmits the signals to the node device connected tothe MUX device 102.

The selecting operation is performed by selection circuits (not shown inthe attached drawings) in the MUX devices 101 and 102, and the selectioncircuits select one of the input signals as a received signal from aradio at an external instruction. The interface circuit 1 a processeseach STM-N signal input through the optical transmission lines 110 and120, and then outputs the results to the V polarizationtransmitter/receiver 2 a and the H polarization transmitter/receiver 3a. The interface circuit 1 b processes each STM-N signal input throughthe optical transmission lines 150 and 160, and then outputs the resultsto the V polarization transmitter/receiver 2 b and the H polarizationtransmitter/receiver 3 b.

The interface circuit la processes the base band digital signals fromthe V polarization transmitter/receiver 2 a and the H polarizationtransmitter/receiver 3 a, and then outputs them to the opticaltransmission lines 130 and 140. The interface circuit 14 b processes thebase band digital signals from the V polarization transmitter/receiver 2b and the H polarization transmitter/receiver 3 b, and then outputs themto the optical transmission lines 170 and 180.

Each of the V polarization transmitter/receiver 2 a and the Hpolarization transmitter/receiver 3 a modulates a signal from theinterface circuit 1 a and converts the result to a radio frequency ofthe RF band, and then transmits it to the radio 10 b, which is anopposite station, through the circulators 4 a and 5 a, and the antenna 6a. Each of the V polarization transmitter/receiver 2 b and the Hpolarization transmitter/receiver 3 b modulates a signal from theinterface circuit 1 b and converts the result to a radio frequency ofthe RF band, and then transmits it to the radio 10 a, which is anopposite station, through the circulators 4 b and 5 b, and the antenna 6b.

The signal received by the antenna 6 a is input to the V polarizationtransmitter/receiver 2 a and the H polarization transmitter/receiver 3 athrough the circulators 4 a and 5 a. Each of the V polarizationtransmitter/receiver 2 a and the H polarization transmitter/receiver 3 aconverts the RF received signal to a signal of an intermediate frequencyband and demodulates the result, and then outputs a base band digitalsignal, which is a demodulation signal, to the interface circuit 1 a.

The signal received by the antenna 6 b is input to the V polarizationtransmitter/receiver 2 b and the H polarization transmitter/receiver 3 bthrough the circulators 4 b and 5 b. Each of the V polarizationtransmitter/receiver 2 b and the H polarization transmitter/receiver 3 bconverts the RF received signal to a signal of an intermediate frequencyband and demodulates the result, and then outputs a base band digitalsignal, which is a demodulation signal, to the interface circuit 1 b.

FIG. 5 shows the configuration of the interface circuits la and lb. Thecomponents also shown in FIG. 4 are assigned the same referencenumerals. As shown in FIG. 5, each of the interface circuits 1 a and 1 bis configured by the STM-N input interface circuits 11 and 12, and theSTM-N output interface circuits 13 and 14.

The STM-N input interface circuit 11 converts the STM-N signal inputfrom the MUX device 101 (102) through the optical transmission line 110(150) to an NRZ (non-return-to-zero) signal, obtains framesynchronization, processes a signal of SOH (section overhead), etc., andthen outputs the resultant signal to the V polarizationtransmitter/receiver 2 a (2 b). The STM-N input interface circuit 12converts the STM-N signal input from the MUX device 101 (102) throughthe optical transmission line 120 (160) to an NRZ signal, obtains framesynchronization, processes a signal of SOH, etc., and then outputs theresultant signal to the H polarization transmitter/receiver 3 a (3 b).

The STM-N output interface circuit 13 converts the base band digitalsignal from the V polarization transmitter/receiver 2 a (2 b) to anSTM-N signal, and then transmits it to the optical transmission line 130(170). The STM-N output interface circuit 14 converts the base banddigital signal from the H polarization transmitter/receiver 3 a (3 b) toan STM-N signal, and then transmits it to the optical transmission line140 (180).

Then, the operation of the wireless communication system shown in FIG. 4is explained below by referring to FIGS. 4 and 5. The operation isexplained using the radio 10 a as a transmitter and the radio 10 b as areceiver.

In FIGS. 4 and 5, one of the two STM-N signals output from the MUXdevice 101 is input to the STM-N input interface circuit 11 of theinterface circuit la through the optical transmission line 110, and theother is input to the STM-N input interface circuit 12 of the interfacecircuit la through the optical transmission line 120.

Each of the STM-N input interface circuits 11 and 12 performs a CMI(coded mark inversion)/NRZ conversion on an input STM-N signal, obtainsframe synchronization, and performs the SOH signal processing. Then, theSTM-N input interface circuit 11 outputs a base band digital signal,which is a result of processing an input STM-N signal, to the Vpolarization transmitter/receiver 2 a. The STM-N input interface circuit12 outputs a base band digital signal, which is a result of processingan input STM-N signal, to the H polarization transmitter/receiver 3 a.

Each of the V polarization transmitter/receiver 2 a and the Hpolarization transmitter/receiver 3 a modulates a signal input from theinterface circuit la, converts the result to a radio frequency of an RFband, and then outputs a conversion result to the antenna 6 a throughthe circulators 4 a and 5 a. Signals from the V polarizationtransmitter/receiver 2 a and the H polarization transmitter/receiver 3 aare combined at the antenna 6 a, and transmitted as a co-channeltransmission from the antenna 6 a to the radio 10 b. The frequencydistribution in the co-channel transmission is the co-channeldistribution shown in FIG. 2A, and the signals from the V polarizationtransmitter/receiver 2 a and the H polarization transmitter/receiver 3 aare transmitted using the polarization plane having the same frequenciesorthogonal to each other as shown in FIG. 2A.

That is, the signal from the V polarization transmitter/receiver 2 a istransmitted as a V polarization signal from the antenna 6 a, andreceived by the radio 10 b through one of the current radio circuit andthe standby radio circuit between the radios 10 a and 10 b. The signalfrom the H polarization transmitter/receiver 3 a is transmitted as an Hpolarization signal from the antenna 6 a, and received by the radio 10 bthrough the other circuit of the current radio circuit and the standbyradio circuit.

The V polarization transmitter/receiver 2 a and the H polarizationtransmitter/receiver 3 a use the same frequency F0 (refer to FIG. 2A) asan RF frequency. Therefore, as compared with the system shown in FIG. 1in which the interleave distribution shown in FIG. 2B is applied, thesystem shown in FIG. 4 effectively uses the frequency.

The signal received by the antenna 6 b of the radio 10 b is separated asa V polarization signal or an H polarization signal, and input to the Vpolarization transmitter/receiver 2 b or the H polarizationtransmitter/receiver 3 b. That is, a V polarization signal is input tothe V polarization transmitter/receiver 2 b through the circulator 4 b,and an H polarization signal is input to the H polarizationtransmitter/receiver 3 b through the circulator 5 b.

Each of the V polarization transmitter/receiver 2 b and the Hpolarization transmitter/receiver 3 b converts an RF received signal toa signal of an intermediate frequency band and then demodulates theconverted signal, and outputs a demodulated base band digital signal tothe interface circuit lb. The V polarization transmitter/receiver 2 band the H polarization transmitter/receiver 3 b can adopt the crosspolarization interference compensation system. In the embodiment of thepresent invention, the orthogonal polarization transmission is performedbetween the radios 10 a and 10 b as described above. Therefore, therecan be a problem of inter-polarization interference. However, byadopting the cross polarization interference compensation system, theeffect of the inter-polarization interference can be suppressed, therebyrealizing a desired wireless transmission.

A base band digital signal from the V polarization transmitter/receiver2 b is input to the STM-N output interface circuit 13 of the interfacecircuit 1 b, and a base band digital signal from the H polarizationtransmitter/receiver 3 b is input to the STM-N output interface circuit14 of the interface circuit 1 b.

Each of the STM-N output interface circuits 13 and 14 processes the SOHof an input base band digital signal, and converts the signal to anSTM-N signal. Then, the STM-N output interface circuit 13 transmits theSTM-N signal to the optical transmission line 170, and the STM-N outputinterface circuit 14 transmits the STM-N signal to the opticaltransmission line 180.

The MUX device 102 selects one of the two STM-N signals input throughthe optical transmission lines 170 and 180, divides the selected signalinto a plurality of signals, and then transmits them to the node deviceconnected to the MUX device 102 itself.

For example, if the current system comprises the V polarizationtransmitters/receivers 2 a and 2 b, the STM-N input interface circuit11, the STM-N output interface circuit 13, and the optical transmissionlines 110, 130, 150, and 170, and the standby system comprises the Hpolarization transmitter/receivers 3 a and 3 b, the STM-N inputinterface circuit 12, the STM-N output interface circuit 14, and theoptical transmission lines 120, 140, 160, and 180, then the MUX device102 normally selects the STM-N signal of the current system inputthrough the optical transmission line 170 as a received signal from theradio 10 b. However, if a fault occurs in the current system, the MUXdevice 102 switches from the current system to the standby system byselecting the STM-N signal of the standby system input through theoptical transmission line 180 as a received signal from the radio 10 b.

In the wireless communication system shown in FIG. 1, a radio uses theMSP system by selecting one of the two STM-N signals input from the MUXdevice and branching it into a signal of the current system and a signalof the standby system. Therefore, there is a common portion in theradio. Meanwhile, in the embodiment of the present invention, since aradio transmits to another radio the two STM-N signals input from theMUX device as a signal of the current system and a signal of the standbysystem, there is no common portion in the radio, and the input andoutput of a STM-N signal in the device is completely duplexed.Therefore, although a fault occurs in one of the current system and thestandby system, it can be relieved.

In the wireless communication system shown in FIG. 1, the selectioncircuit 37 (refer to FIG. 3) in the radio switches between the currentsystem and the standby system. On the other hand, according to thepresent invention, the MUX device switches between the current systemand the standby system. Therefore, it is not necessary to controlswitching in the radio, thereby simplifying the configuration of theradio.

Additionally, in the embodiment of the present invention, since duplexis realized in the system different from the MSP system, it is notnecessary to configure the interface circuit in the MST configuration.That is, since the interface circuit does not select one of the twoSTM-N signals input from the MUX device and branch it, only thesubordinate synchronization in which the clock of the interface circuitis subordinate to and in synchronization with the clock of thetransmission line. Therefore, the interface circuit can have the RST(regenerator section termination) configuration requiring no CLKproviding circuit or MSOH terminating circuit, thereby simplifying theconfiguration of the radio.

Furthermore, the embodiment of the present invention performs orthogonalpolarization transmission using the polarization with the samefrequencies orthogonal to each other in the current radio circuit andthe standby radio circuit between the radios. Thus, the effective use offrequency can be realized.

INDUSTRIAL APPLICABILITY

The effect of the present invention is that a failure can be necessarilyrelieved so far as the fault occurs only in one of the current systemand the standby system (simple fault) because the current system and thestandby system are independent of each other by removing the commonportion from a wireless communication apparatus.

1. A wireless communication apparatus in an MSP system having aredundant configuration and receiving same signals through a currentcable circuit and a standby cable circuit, comprising: currentcommunication means comprising current cable circuit configured by acurrent STM-N input interface circuit for receiving a signal from an MUXdevice connected to a node, a current STM-N output interface circuit foroutputting a signal to the MUX device, a current transmitter/receiverconnected to the current STM-N input interface circuit, and a currentcirculator connected to the current transmitter/receiver, and a currentradio circuit, configured by an antenna connected to the currentcirculator, for transmitting/receiving a signal to and from anotherradio device; and standby communication means comprising a standby cablecircuit configured by a standby STM-N input interface circuit forreceiving a signal from the MUX device, a standby STM-N output interfacecircuit for outputting a signal to the MUX device, a standby.transmitter/receiver connected to the standby STM-N input interfacecircuit and the standby STM-N output interface circuit, and a standbycirculator connected to the standby transmitter/receiver, and a standbyradio circuit. configured by an antenna connected to the standbycirculator, for transmitting/receiving a signal to and from the otherradio device, uses a co-channel radio frequency distribution. andcompletely duplexes input through output of an STM-N signal in theapparatus.
 2. The wireless communication apparatus according to claim 1,characterized in that the radio signals transmitted from the currentcommunication means and the standby communication means are polarizationsignals having the same frequencies and different polarizationdirections.
 3. The wireless communication apparatus according to claim1, characterized in that: the current communication means receives asignal transmitted from a current communication means of the otherwireless communication apparatus through the current radio circuit, andtransmits the received signal to the MUX apparatus through the currentcable circuit; and the standby communication means receives a signaltransmitted from a standby communication means of the other wirelesscommunication apparatus through the standby radio circuit, and transmitsthe received signal to the MUX apparatus through the standby cablecircuit.
 4. (canceled)
 5. A wireless communication system for performingwireless communications in an MSP system using wireless communicationapparatuses which have a redundant configuration, receive same signalsfrom MUX device to each wireless communication apparatus through acurrent cable circuit and a standby cable circuit, each of the wirelesscommunication apparatuses comprising: current communication meanscomprising a current cable circuit configured by a current STM-N inputinterface circuit for receiving a signal from an MUX device connected toa node, a current STM-N output interface circuit for outputting a signalto the MUX device, a current transmitter/receiver connected to thecurrent STM-N input interface circuit and the current STM-N outputinterface circuit, and a current circulator connected to the currenttransmitter/receiver, and a current radio circuit, configured by anantenna connected to the current circulator, for-transmitting/receivinga signal to an from another-radio device; and standby communicationmeans comprising a standby cable circuit configured by a standby STM-Ninput interface circuit for receiving a signal from the MUX device, astandby STM-N output interface circuit for outputting a signal to theMUX device, a standby transmitter/receiver connected to the standbySTM-N input interface circuit and the standby STM-N output interfacecircuit, and a standby circulator connected to the standbytransmitter/receiver, and a standby radio circuit, configured by anantenna connected to the standby circulator, for transmitting/receivinga signal to and from the other radio device, uses a co-channel radiofrequency distribution, and completely duplexes input through output ofan STM-N signal in the apparatus.
 6. The wireless communication systemaccording to claim 5, characterized in that the radio signalstransmitted from the current communication means and the standbycommunication means are polarization signals having the same frequenciesand different polarization directions.
 7. The wireless communicationsystem according to claim 5, characterized in that: the currentcommunication means receives a signal transmitted from a currentcommunication means of the other wireless communication apparatusthrough the current radio circuit, and transmits the received signal tothe MUX apparatus through the current cable circuit, and the standbycommunication means receives a signal transmitted from a standbycommunication means of the other wireless communication apparatusthrough the standby radio circuit, and transmits the received signal tothe MUX apparatus through the standby cable circuit.
 8. (canceled) 9.The wireless communication apparatus according to claim 2, characterizedin that: the current communication means receives a signal transmittedfrom a current communication means of the other wireless communicationapparatus through the current radio circuit, and transmits the receivedsignal to the MUX apparatus through the current cable circuit; and thestandby communication means receives a signal transmitted from a standbycommunication means of the other wireless communication apparatusthrough the standby radio circuit, and transmits the received signal tothe MUX apparatus through the standby cable circuit.
 10. The wirelesscommunication system according to claim 6, characterized in that: thecurrent communication means receives a signal transmitted from a currentcommunication means of the other wireless communication apparatusthrough the current radio circuit, and transmits the received signal tothe MUX apparatus through the current cable circuit, and the standbycommunication means receives a signal transmitted from a standbycommunication means of the other wireless communication apparatusthrough the standby radio circuit, and transmits the received signal tothe MUX apparatus through the standby cable circuit.